The channel over the purfling, making-concept

These drawings are from the Titian Stradivari (Strad poster).  I can not give credit for the drawings as am not aware of who did them.  They are simple and clear.

I generally make my instruments following the Classic Cremona Method, the purfling is inlayed once the internal thickness is complete.  In the case of this violin I have glued the top and still have to cut the f-holes which means that the thinkness is not complete yet.

I use a number 7 gouge for the first cut directly on the purfling.  Then I make a second cut with a number 6.

I am very fond of a number 3 very flat Wolf gouge that allows me to shape the arching with extreme precision. I could use the scraper right after it.  But I don't and I go along the grain with a Cremona Tools 18mm finger plane.

From this image you can guess best the depth of the channel and its effect on sound production.